阅读python文档

python/py.md

@@ -692,5 +692,73 @@ total 4
 drwxrwxrwx 1 asahi asahi 4096 Feb  7 21:39 venv
 ```
 
+## 正则
+python通过re模块提供了正则表达式的支持
+### match
+match方法定义如下所示
+```py
+re.match(pattern, string, flags=0)
+```
+match方法使用示例如下所示：
+```py
+import re
 
 
+def main():
+    match_res = re.match("(?P<prefix>.*) father", "i am your father")
+    if match_res is None:
+        print("failed match")
+        return
+    print(match_res.group("prefix")) # i am your
+    print(match_res.group(0)) # i am your father
+
+
+main()
+```
+
+### search
+search方法定义如下所示
+```py
+re.search(pattern, string, flags=0)
+```
+search方法使用示例如下所示
+
+### pattern
+类似java，re提供了compile方法，返回正则编译后的pattern，并通过pattern执行操作
+
+#### findall
+`pattern.findall`方法会返回所有匹配的字符串
+```py
+import re
+
+
+def main():
+    msg = '''although i use amd graphic card, i view it as a trash for its bad performance in ai.
+    nvidia is also trash because its crazy price, fuck amd and nvidia!'''
+    pattern = re.compile("(amd|nvidia)\\s+(graphic card)?")
+    search_res_list = pattern.findall(msg)
+    print(search_res_list)
+
+
+main()
+
+# [('amd', 'graphic card'), ('nvidia', ''), ('amd', '')]
+```
+#### finditer
+`pattern.finditer`会返回所有匹配的match对象
+```py
+import re
+
+
+def main():
+    msg = '''although i use amd graphic card, i view it as a trash for its bad performance in ai.
+    nvidia is also trash because its crazy price, fuck amd and nvidia!'''
+    pattern = re.compile("(amd|nvidia)\\s+(graphic card)?")
+    search_res_list = pattern.finditer(msg)
+    print([e.group(0) for e in search_res_list])
+
+
+main()
+
+# ['amd graphic card', 'nvidia ', 'amd ']
+```